k-ET_2Cu_2(CN)_3 provides an excellent experimental system for studying the 2D S=1/2 frustrated triangular lattice Heisenberg model. A spin-liquid state persists in this system down to 20mK, with associated temperature-dependent NMR relaxation indicating an excitation spectrum extending to very low energies. Field-dependent muSR studies have been made that are providing evidence of the 2D spin diffusion associated with a 2D spin-liquid state which has a diffusion constant strongly suppressed compared to that of a classical 2D paramagnet. This indicates a significant difference from the 1D quantum paramagnetic case, where the spinon diffusion rate measured using muSR was found to be consistent with the exchange constant inferred from the high temperature susceptibility. Beamtime is requested to extend the studies to the temperature region below 10K using the EMU sorb in flypast mode